The present invention relates to cesium or rubidium or both and the recovery of these elements from secondary ore. The present invention further relates to a purified ore that contains cesium and a unique combination of others minerals and/or elements.
Cesium salts, such as cesium formate, are increasingly being discovered as useful components or additives for a variety of industrial applications, such as in the hydrocarbon recovery areas. However, deposits of “primary” ore, that is, ore that contains high amounts of cesium with insignificant amounts of undesirable impurities, are rare, and operators have long sought techniques to enhance recovery of cesium and/or rubidium from known deposits of secondary ore containing cesium and/or rubidium.
However, cesium-containing secondary ore, while available, presents major problems with regard to recovering the cesium from such ore. For instance, the expense of recovering significant amounts of cesium from low yield ore can be quite time consuming and expensive based on known methods. Also, with known techniques, it is very difficult and expensive to separate cesium from certain undesirable metals or minerals that can typically be found with deposits of cesium-containing secondary ore. For instance, many cesium-containing secondary ore deposits have significant lithium containing minerals, such as, but not limited to, phosphate minerals, such as Amblygonite, Montebrasite, and/or cesium-substituted Lithiophosphates. If the phosphate minerals which contain significant amounts of lithium, and frequently sodium, are not significantly separated from the secondary ore, the lithium can then present serious impediments to the commercial use of the cesium-containing fraction of the secondary ore in a variety of industries, such as in the hydrocarbon recovery area with regard to fluids, such as drilling fluids, completion fluids, packer fluids, and the like.
In more detail, one beneficial use of cesium is as cesium formate in solution to create high density well fluids which are extremely useful in deep drilling oil and gas wells. If the lithium is present at excessive levels in the fluids, the fluid cannot be manufactured with a sufficient amount of cesium in solution to achieve the high fluid density required for well drilling fluids. If the lithium levels exceed critical parameters, the cesium-containing salt will precipitate out of solution before reaching the needed density to work as a suitable well fluid, which will make the fluid unsuitable for hydrocarbon recovery.
In using primary ore sources, the presence of lithium is not a significant problem because the cesium-containing primary ore deposits, namely, pollucite, can be recovered without any significant levels of lithium-containing phosphate minerals being present. Thus, this problem is unique to cesium-containing secondary ores. In addition, if the lithium is not substantially removed from the secondary ore before chemical processing to recover cesium, the lithium, as well as any sodium, can be excessively challenging to remove from the cesium during traditional downstream wet chemical processing of the ore (e.g., beginning with acid digestion). Adding to this challenge is the variable presence of the levels of these lighter alkalis, as introduced with the ore prior to wet chemical processing.
These same problems also can exist with rubidium containing ore or ore containing cesium and rubidium.
Accordingly, there is a need in the industry to develop methods for recovering the highly sought and valued minerals bearing cesium, rubidium, or both, from secondary ore, also referred to as cesium-containing secondary ore. There is a further need to create methods that will significantly reduce the content of minerals bearing lithium, and the other lighter alkali, impurities and other mineral and/or metal impurities in the recovered cesium, rubidium, or both, so as to avoid the significant challenges of wet chemical processing, as well, the viability of brine products, as per those problems described above.